Thomas Pieters was in a four-way tie at the World Super 6 Perth after a late bogey cost him the outright lead after the second round.
Pieters recovered from double-bogeys on the second and third holes in the opening round to reach two under, yet his next 18 was relatively uneventful on Friday.
And the Belgian looked to have done enough to head the field at the halfway stage with seven birdies between the fifth and 14th holes.
But a second bogey of the day at the 17th saw him fall back to eight under overall, following a second-round six-under 66, as he joined three other players at the top of the leaderboard.
— The European Tour (@EuropeanTour) February 15, 2019
Panuphol Pittayarat, Ryan Fox and Matthew Griffin each have a share of the lead after setting the early standard. Matt Jager, who finished after Pieters, briefly threatened to join them but finished one shot back.
Miguel Tabuena had equalled the European Tour record for birdies on a front nine on Thursday to seize a share of the lead, but he collapsed in the second round, carding a six-over 78 to fall to joint-49th, just above the cut line.
Only one shot better off was Kristoffer Reitan, who matched Tabuena in the opening round, as the Norwegian slipped back due to a triple-bogey at the third.